Field of the Invention
This invention relates to apparatus for making samples for use in infrared or other spectropscopic analysis.
An evacuable KBr (potassium bromide) die is extensively used in infrared analysis. In this die, a sinterable infrared transmitting powder, usually potassium bromide or potassium chloride, mixed with the sample under investigation, is pressed typically at a load of about 30 tons per square inch to produce a disc or pellet. This is effected under vacuum so as to help remove water from the sample and to reduce fogging. The disc is then placed in the appropriate instrument for analysis.
In the known method of producing such a disc described above, the mixture of sample and substrate powder is placed between two pellets and a piston is used to apply force to one of the pellets in order to apply the compressive load. On one side of the die is an evacuation outlet which is used to evacuate the die during compression. This is done in order to reduce the amount of water in the disc to avoid the results of the infrared analysis from being contaminated by the absorption bands or water.